We have an F350 dually that currently is used to pull our 32' travel trailer toy hauler, it's about 8000lbs loaded without a toy, closer to 10 with. The truck we have is overkill for what we have now, but we plan on upgrading to a 5er with a 12,000lb dry weight within the next year.
My advice is, buy the biggest truck you can, even if it is still overkill for what you're pulling. Very few people regret buying a bigger truck, but there's tons of people (including us originally) that regret not buying a bigger truck to begin with.
My first question for you is, what toys do you want to haul in your toy hauler?
2020 Keystone Montana High Country 294RL
2017 Ford F350 DRW King Ranch
2021 Ford F350 SRW Lariat Tremor